For millions of people approaching old age, developing dementia is a frightening prospect — in particular if there is a family history of the disease.
Dementia is the loss of mental abilities and most commonly occurs late in life. Of all persons over age 65, 5-8% are demented. This percentage increases considerably with age. Twenty-five to 50% of people over 85 are affected. The most common form of dementia, Alzheimer’s disease, accounts for 50-75% of all cases of dementia.
What is clear from numerous observational studies is that keeping mentally active throughout life reduces the risk of developing dementia. When the brains of former mentally active people are dissected, pathologists often find that their brains are riddled with Alzheimer plaques, and yet those people had shown no signs of impaired memory when they were alive.
Dr. Michael Valenzuela’s research
Research from the School of Psychiatry at UNSW, led by Dr. Michael Valenzuela, showed that people who kept their brains active, for example, through work, leisure activities, or brain training, had half the risk of suffering dementia.
Dr. Valenzuela’s research provided the most convincing evidence to date that complex mental activity across people’s lives significantly reduces the risk of dementia. The researchers found that such activity almost halves the incidence of dementia.
The paper, published in Psychological Medicine, is the first comprehensive review of the research in the field of ‘brain reserve’, which looks at the role of education, occupational complexity, and mentally stimulating lifestyle pursuits in preventing cognitive decline. The paper integrated data from 29,000 individuals across 22 studies from around the world.
“Until now there have been mixed messages about the role of education, occupation, IQ, and mentally stimulating leisure activities, in preventing cognitive decline. Now the results are much clearer,” said Dr. Valenzuela. “It is a case of ‘use it or lose it.’ If you increase your brain reserve over your lifetime, you seem to lessen the risk of Alzheimer’s and other neurodegenerative diseases.”
The key conclusion is that individuals with high brain reserve have a 46% decreased risk of dementia, compared to those with low brain reserve. All the studies assessed agreed that mentally stimulating leisure activities, even in late life, are associated with a protective effect.
“This suggests that brain reserve is not a static property, nor that it is determined by early life experiences such as level of education, socio-economic deprivation, or poor nutrition,” said Dr. Valenzuela. “It is never too late to build brain reserve.”
Dr. Valenzuela’s previous research showed that after five weeks of memory-based mental exercise, participants increased brain chemistry markers in the opposite direction to that seen in Alzheimer’s disease. “The interesting point here is that this change was concentrated to the hippocampus, a part of the brain first affected in dementia,” said Dr. Valenzuela.